U.S. Pat. No. 4,898,591 describes catheter tubing formed of a blend of ester-linked PEBA (poly(ester-block-amide) with nylon 11. A lubricious hydrogel coating is applied to the surface. The lubricious coating may be a copolymer of polyurethane and polyvinylpyrrolidone or cross-linked copolymer of polyethylene oxide and polyhydroxyethyl methacrylate.
Surmodics, Inc. has described polymerizable compositions employing polyvinylpyrrolidone polymers that include photoinitiator groups thereon and use of such compositions on Pebax® polymer substrates in U.S. Pat. No. 7,348,055, US 2006/0030669 and US 20060240072. These compositions however are expensive to produce as the polymers with photoinitiator groups thereon must be specially prepared.
U.S. Pat. Nos. 5,585,057 and 5,433,713, Trotta, describe catheter tubing of ester-linked PEBA (“polyesteretheramides”) such as Pebax® polymers have a blooming phenomena that is attributed to the ester linkage in these polymers. The blooming develops on accelerated aging and detrimentally affects adherence of hydrophilic coatings. These documents propose blending polyesteretheramide polymers having a Shore D hardness of greater than 70 with polyetheramides having no ester linkages, or with polyamides, to prevent particle blooming.
U.S. Pat. No. 6,629,961, Israelsson, also describes a blooming phenomena that occurs when ester-linked PEBA polymers (e.g. Pebax® polymers) are used for catheter tubing and teaches to use sequentially applied coatings of polyisocyanate and polyvinylpyrrolidone to avoid adherence problems despite the fact that blooming is sometimes observed after some months storage. This is attributed to the manner in which the coating is applied. The sequential coating provides a polyvinylpyrrolidone-polyurea interpolymer coating. The polyisocyanate coating step, however, substantially adds to the cost of this process.
U.S. Pat. No. 5,693,034 Busemi et al describes a lubricious coating for insertable medical devices such as catheters, balloons, and the like that is formed by polymerizing a polyfunctional acrylate monomer in a composition that also includes an uncrosslinked hydrogel polymer. Specific uncrosslinked hydrogel polymers that may be used include polyethylene oxide, polyacrylic acid, polyacrylamide, poly(sodium-4-styrenesulfonate), poly(3-hydroxybutyric acid), polyvinylpyrrolidone, and 2-hydroxyethyl methacrylate. One particular formulation according to U.S. Pat. No. 5,693,034 that has been commercialized is a lubricious coating in which the polyacrylate network is a polymer of neopentyl glycol diacrylate and the hydrogel polymer is polyethylene oxide. This coating has been successfully employed without significant problem on diverse substrates such as polyethylene, polyester, metals, polyester elastomers, and the like. The coating has the advantage that it involves a single application and that it can be photocured rapidly. However, when applied to substrates of Pebax® polymers that are susceptible to blooming, this polyethylene oxide/polyacrylate does not prevent particulate from passing therethrough. Under high humidity accelerated aging conditions high particle counts develop rapidly.